1. Turn your Sony PCG-FX105K laptop over.
2. Find the laptop battery release button lock for your Sony PCG-FX105K laptop.
3. Now that your Sony PCG-FX105K laptop battery is unlocked, find the battery release button down.
4. Holding the laptop battery release button, gently pull your battery away from the laptop.
5. Now that your Sony PCG-FX105K battery is removed, grab your replacement Sony PCG-FX105K battery for installation.
6. Insert the battery into the slot. Push the Sony PCG-FX105K battery towards the laptop and secure it in place.